Patients with subacromial pain in primary care : Assessment and efficacy of physiotherapy-guided exercise treatment

Sammanfattning: Background: Shoulder pain is a common musculoskeletal disorder and 40-74% of the patients attending primary healthcare with a shoulder disorder are diagnosed with subacromial pain. Subacromial pain is characterized by restricted and painful movement of the arm that leads to difficulties in performing arm-related activities and often affects the quality of life profoundly, with respect to everyday function, work capacity, sleep quality and mental health. It is crucial that the measurements used to evaluate shoulder function and treatment response have acceptable psychometric properties and also that they are patients-specific and time-efficient to administer. For patients with subacromial pain, exercises are recommended as first-line treatment but consensus about which exercises and dosage to recommend has not been reached. The lack of evidence for one specific exercise model may be partly due to heterogeneity among this group of patients. The overall aim of this thesis were to evaluate the efficacy of a previously tested exercise strategy for patients with subacromial pain in a primary care setting, to describe the heterogeneity with possible subcategories among patients with subacromial pain, and finally to validate and adjust the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire for more diagnosis-specific clinical assessment. Methods: The four papers in this thesis are based on two clinical studies, one randomized controlled trial (RCT) and one clinical cohort. The participants in both studies were patients with subacromial pain attending physiotherapist (PT) in a primary care setting. Two of the papers are based on psychometric analyses, with evaluation of construct validity and responsiveness for the DASH when used to evaluate shoulder function in patients with subacromial pain, and also calculation of minimal important change (MIC) for a diagnosis-specific short version of DASH (DASH 7). A third paper describe clinical presentation in patients with subacromial pain, based on the components active range of motion (AROM), rotator cuff function and scapular kinematics and the fourth paper evaluated the efficacy of a 3-month specific exercise strategy in comparison to an active control strategy. Results: Seven items from the original DASH were identified as being the most important in evaluating patients with subacromial pain (resulting in the DASH 7 questionnaire). The DASH 7 shows good responsiveness, can discriminate between patients who perceive themselves as improved and those who do not, and maintain a high level of internal consistency for the assessment of shoulder function in patients with subacromial pain, using only a quarter of the items of the original DASH. Based on clinical presentation, patients with subacromial pain in the primary care setting comprise a heterogeneous group. Rotator cuff dysfunction, defined as pain during resisted isometric muscle-testing, is very frequently present while limitation in active range of motion and scapular dyskinesia are less common. After three months of exercise, both groups in the RCT had significantly improved with no between group difference as measured with the primary CM-score. However, as measured with the DASH and the DASH 7, the patients in the specific exercise group was significantly more improved compared to those in the active control group. Conclusions: The DASH 7 questionnaire is a short patient-reported outcome measurement (PROM) with good responsiveness, specific for patients with subacromial pain. Heterogeneity was confirmed with identified variability in AROM, rotator cuff function and scapular kinematics in clinical presentation which confirms that these components are important in the clinical examination of patients with subacromial pain. Shoulder function evaluated with the CM score did not improve to a significantly different degree between the two groups studied. The specific exercises might not be necessary for all patients in the primary care setting to achieve a clinically relevant improvement. However, the specific exercise strategy was significantly better when improvement was assessed by DASH and DASH 7, and this leads us to recommend this strategy, with its progressive loading of the rotator cuff muscles and scapula stabilizers, as first choice, provided that it is tolerated by the patient.